The 連用形 (ren'yōkei, “continuative or stem form”) of verb 暮れる (kureru, “to set (said of the sun or moon), to get dark”), from the way that China lies to the west of Japan, in the direction of the setting sun.[1] Originally referred more specifically to the ancient State of Wu (roughly analogous with the modern Jiangnan region), and later referring to China as a whole.[1][2]